Abstract
We present a density-functional theory study of low-density bromination of graphene and graphite, finding significantly different behavior in these two materials. In graphene, we find a new form where the molecule sits perpendicular to the graphene sheet with an extremely strong molecular dipole. The resultant – has an empty orbital located in the graphene electronic cloud. Bromination opens a small (86-meV) band gap and strongly dopes the graphene. In contrast, in graphite, we find is most stable parallel to the carbon layers with a slightly weaker associated charge transfer and no molecular dipole. We identify a minimum stable concentration in graphite, finding low-density bromination to be endothermic. Graphene may be a useful substrate for stabilizing normally unstable transient molecular states.
- Received 14 December 2010
DOI:https://doi.org/10.1103/PhysRevB.83.045411
© 2011 American Physical Society